GaAs-chip-based mid-infrared supercontinuum generation

Area of Science:

• Photonics and Laser Technology
• Materials Science
• Spectroscopy

Background:

• Mid-infrared (MIR) light enables high-resolution molecular spectroscopy for medical diagnostics.
• Synchrotron sources provide MIR light but are large and inaccessible.
• Table-top MIR light sources are needed to advance biological and medical research.

Purpose of the Study:

• To introduce orientation-patterned gallium arsenide (OP-GaAs) waveguides as a novel platform for MIR supercontinuum generation.
• To develop a compact, high-brightness MIR light source as an alternative to synchrotrons.
• To explore the potential for power scaling and advanced applications.

Main Methods:

• Fabrication of OP-GaAs waveguides optimized for MIR supercontinuum generation.
• Tandem optimization of waveguides and fiber-based pump lasers for matched group velocities.
• Pumping waveguides at 2750 nm with few-nanojoule pulses to achieve supercontinuum generation.

Main Results:

• Achieved supercontinuum generation spanning 4 to 9 µm using OP-GaAs waveguides.
• The novel MIR source demonstrated a brightness 20 times greater than third-generation synchrotron sources.
• Nonlinear dynamics were shown to be tunable by adjusting waveguide and laser parameters.

Conclusions:

• OP-GaAs waveguides offer a versatile platform for developing high-brightness MIR supercontinuum sources.
• This technology enables advanced high-resolution spectroscopy and imaging.
• Potential for power scaling to watt-level ultra-broadband frequency combs in the MIR is feasible.